The invention relates to a communication system comprising a controller arranged for service implementation, which controller is coupled to a data bank and, via at least one switch, to at least one terminal unit.
Patent Application WO 92/11724 has disclosed a communication system which comprises a communication network (switched telephone network, service control point) comprising several switches and terminal units coupled to these switches. Certain switches included in the communication network are used, on the one hand, for carrying out switching functions with various terminal units (for example, telephone traffic) or further switches and, on the other hand, for switching to a network (overlay network) arranged for service implementation. One service of the German Post-Office Telekom is, for example, the private information service Tele-Info-Service.
If a subscriber dials a specific service number (for example, 0190 . . . ), a switch (service switching point) recognizes this and establishes a connection to this network arranged for service implementation. At least certain switches not only perform their normal call switching, but also process calls and switch them through to the service implementing network.
If a subscriber wishes to use a service (service subscription, service providing), the subscriber contacts the service operator and receives, for example, in written form, the data necessary for using the service (for example, identification number, registration number). The use of the service can also be cancelled, but only in written form. A subscriber, however, may effect a change of service parameters from his terminal unit. For example, a call diversion may be changed (compare "Neue Dienste im intelligenten Telefonnetz" by Wilhelm Krusch, R. v. Decker's Verlag, G. Schenk Heidelberg, 1993, page 156).